Follow Path constraint moves object away from curve?
Positioning the camera to the starting point of the curve isn't necessary.

The camera's location defines an offset from it's constrained location. So to remove this offset, reset the camera's location to 0,0,0 by selecting the camera and pressing &#9095; AltG.

As an example of how this works, the camera is positioned at the start of the curve (2 BU above the world center):



When the constraint is defined, the camera is now 2 BU above the start of the curve, instead of the world center:



This is because the camera location is now relative to a point along the curve defined by the constraint, in this case the beginning.